The present disclosure relates to a network controller and a network controlling method, and in particular to a network controller and a network controlling method that allow achieving power saving by reducing communication speed during the sleep state.
In recent years, a network interface card (hereinafter referred to as an NIC) has been used for connecting a computer and another device to the network in transmitting and receiving information and data between the computer and the other device via the network.
The NIC is attached to an extension slot (bus) such as a computer and a workstation on the LAN that is a network. After connecting the LAN cable to the NIC, the NIC, controlled by driver software, transmits the data.
An example of the NIC technology is a media access controller that can be used for an Ethernet (trademark) of any one of the formats from among 10BASE-T, 100BASE-T, and 10BASE-2, using a single medium access control (MAC) chip.
However, the NIC must constantly receive and process packets from the network and therefore the power needs to be always ON. Also available on the market is a MAC chip that is capable of activating a host device only when it receives a specific Ethernet (trademark) packet (Magic-Packet), but this type has a problem of causing restrictions in practical use due to its dependence on the packet generation capacity of the sending side. In addition, for this reason, there is a growing need for suppressing power consumption during a standby state while maintaining a communication function (the function to process an Ethernet (trademark) packet that is received).
A terminal controller is connected to a terminal device that is connected to another terminal device via a network, and controls the speed of data transfer from the terminal device. A network terminal controller includes a receiving portion and a reception determination portion. The receiving portion receives a data communication request transmitted from the terminal device to the other terminal device within the network. In addition, the receiving portion receives a data communication request transmitted to the terminal device from the other terminal device within the network. The reception determination portion determines whether or not the receiving portion has received the data communication request for a given time. In addition, the network terminal controller includes a sending portion and a speed switching portion. The sending portion transmits the data communication request received by the receiving portion, to the terminal device or the other terminal device within the network at a predetermined data transfer speed. The speed switching portion switches the predetermined speed of the data transfer performed by the sending portion. Then, the speed switching portion switches the data transfer speed to a lower speed when the reception determination portion determines that no data communication request has been received for the given time. When the receiving portion receives a data communication request from the terminal device or the other terminal device within the network, the speed switching portion switches the speed of the data transfer performed by the sending portion to a higher speed. This allows reducing the power consumption of the NIC in a simple manner while maintaining the function of the network communication without change in hardware. As a result, it is possible to suppress the power consumption during a standby time.
In addition, a network device is connected to another network device via a network so as to allow communication at a plurality of communication speeds. During the standby time, if no communication request has been received for a given time, the network device changes the setting by switching the communication speed to a low-speed mode (energy-saving mode) in N levels. The network device, which has received a data communication request from the other network device, completes the communication at a communication speed that is currently set. The network device, after completion of the communication, performs setting by switching the communication speed to a high-speed mode. This allows reducing power consumption. In addition, in the case of transmitting a very small amount of data from the original document, for example, this would prevent such cases where switching the communication speed takes more time for printout that would be promptly performed without the switching, thus securing usability.